This invention relates to a current flow monitor that indicates if current is flowing through a load, for example, a heating cable.
Heating cables are used to protect objects under freezing conditions. For example, it is known to wrap a heating cable around a pipe to protect the pipe from freezing during inclement weather. Depending on the length of the pipe, a cable of appropriate length is selected to adequately protect the pipe along its length. Heating cables are also used to protect other objects such as gutters from freezing. Again, depending on the physical characteristics of the object to be protected, a particular length of heating cables is selected.
Because heating cables are often difficult to inspect once they have been installed, it is difficult, if not impossible, to determine if the heating cable is operating properly. For example, the heating cable may not be operating properly because it may have become disconnected from the power source. Thus, it is usually not known whether the cable is operating properly until the object it was to protect such as a pipe or gutter, for example, freezes. Such a condition often causes serious damage to property and involves difficult and expensive repairs.
It is therefore desirable to provide a monitor for indicating that a load is drawing current. It is also desirable to provide a monitor that is remote from the load it is monitoring so that a determination that the load is drawing current can be easily made. It is also desirable to provide a plug-in monitor that can be used with existing types of heating cables to monitor the current flow through the cables.
In addition, because the load that needs to be monitored can be variable, for example, the load may range from one heating cable of a first length to a heating cable of a second length that is different from the first length, it is also desirable to provide a monitor that can detect a wide range of currents so that the same monitor can be used for variable loads.